import itertools
from collections import deque


def find_peak(x, rise_width, fall_width, min_height=None):
    peaks, peak_idxs = [], []
    peak_candi, peak_candi_idx = -999, 0
    rise_w, fall_w = 0, 0
    for idx, value in enumerate(x):
        if value >= peak_candi:
            peak_candi, peak_candi_idx = value, idx
            rise_w += 1
            fall_w = 0
        else:
            fall_w += 1
            if fall_w > fall_width:
                if (rise_w > rise_width) and ((min_height is None) or (peak_candi > min_height)):
                    peaks.append(peak_candi)
                    peak_idxs.append(peak_candi_idx)
                peak_candi, peak_candi_idx = -999, 0
                rise_w = 0
                fall_w = 0
    return peaks, peak_idxs


def moving_average(data_array, n=3):
    """
    Calcuate the moving average based on the specific data array.
    :param data_array: the array stored data to be calculated.
    :param n: the number of data in one time
    :return: Generate which contains the result
    """
    it = iter(data_array)

    d = deque(itertools.islice(it, n - 1))
    s = sum(d)
    # In the first round, to avoid getting extra element, so need zero in the head of queue.
    d.appendleft(0)
    for elem in it:
        s += elem - d.popleft()
        d.append(elem)
        yield s / float(n)


def crc16(data):
    crc_table = [0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500,
                 0xC5C1, 0xC481, 0x0440, 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40, 0x0A00, 0xCAC1,
                 0xCB81, 0x0B40,
                 0xC901, 0x09C0, 0x0880, 0xC841, 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40, 0x1E00,
                 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41, 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0,
                 0x1680, 0xD641,
                 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040, 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300,
                 0xF3C1, 0xF281, 0x3240, 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441, 0x3C00, 0xFCC1,
                 0xFD81, 0x3D40,
                 0xFF01, 0x3FC0, 0x3E80, 0xFE41, 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840, 0x2800,
                 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41, 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1,
                 0xEC81, 0x2C40,
                 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640, 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101,
                 0x21C0, 0x2080, 0xE041, 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240, 0x6600, 0xA6C1,
                 0xA781, 0x6740,
                 0xA501, 0x65C0, 0x6480, 0xA441, 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41, 0xAA01,
                 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840, 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0,
                 0x7A80, 0xBA41,
                 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40, 0xB401, 0x74C0, 0x7580, 0xB541, 0x7700,
                 0xB7C1, 0xB681, 0x7640, 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041, 0x5000, 0x90C1,
                 0x9181, 0x5140,
                 0x9301, 0x53C0, 0x5280, 0x9241, 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440, 0x9C01,
                 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40, 0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0,
                 0x5880, 0x9841,
                 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40, 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01,
                 0x4DC0, 0x4C80, 0x8C41, 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641, 0x8201, 0x42C0,
                 0x4380, 0x8341,
                 0x4100, 0x81C1, 0x8081, 0x4040]

    crc_hi = 0xFF
    crc_lo = 0xFF

    for w in data:
        index = int(crc_lo) ^ w
        crc_val = crc_table[int(index)]
        crc_temp = crc_val >> 8
        crc_val_low = crc_val - (crc_temp << 8)
        crc_lo = crc_val_low ^ crc_hi
        crc_hi = crc_temp

    return bytes([crc_lo, crc_hi])


if __name__ == '__main__':
    bytes_test = b"\x80\x84\x01"
    a = crc16(bytes_test)
    print(a)
